In general, samples for radionuclide analysis have a variety of shapes, chemical and physical properties. The radiation level may be low in a large sample, or it may be high in a very small sample. In the case where the sample is composed of a material of a high density and a high atomic number, measurement by gamma ray attenuation may be difficult.
Accordingly, the sample should be mounted on the detector of the optimum condition in order that radiation spectrum can be obtained well along with reliable figures. On the other hand, in order to analyze the gamma ray emission nuclide existing in the sample, it is important how the gamma ray penetrates the substance and how the gamma ray shall be detected. High Purity Germanium Gamma Spectroscopy Systems (hereinafter referred to as “HPGe”) which show efficiency at low energy and excellent resolution across the entire energy range is widely used to meet these requirements.
With the use of HPGe in Korea and other countries as described above, there have also been various types of Marinelli beakers (1 L) for charging samples so as to correspond to a detecting device installed. And since a new type of Marinelli beaker recently supplied has become larger by considering the diameter of the detecting device mounted on various HPGe products, a space is formed between the detecting device and the lower portion of the beaker where the detecting device is inserted, thereby increasing the uncertainty of the detection value. Accordingly, it is needed to develop a complementary container that can reduce the experimental error (geometrical uncertainty) occurring during mounting the sample by the space existing between the Marinelli beaker and the detecting device.
The above-mentioned experimental error can be expressed by the following standard uncertainty. That is, the combined standard uncertainty (UC) is the standard uncertainty of the measurement result when the measurement result is obtained from several different input quantities and is obtained by combining the uncertainty (UA) obtained by statistically analyzing a series of observed values and the uncertainty (UB) by the mathematical method as in Equation 1 below when the uncertainty factor (input quantity) is independent.
In other words, by installing the correction container in the space existing on the lower portion of the Marinelli beaker where the detector is contacted, a calibration error that occurs during the equipment calibration as well as a standard deviation that occurs during the repeated experiment can be reduced, and this is related to statistics analytical uncertainty UA.Uc=√{square root over (Ua2+Ub2)}  [Equation 1]
In Equation 1, UC is the combined standard uncertainty, UA is the uncertainty by observation statistics, and UB is the uncertainty by a mathematical method.
On the other hand, the correction container must be replaced since the required size becomes different in order to measure radionuclides in a sample using the small amount of sample measuring bottle. In order to measure radionuclides in a small amount of sample, a small measuring bottle having a capacity of 80 ml should be used. In order to measure radionuclides using a small measuring bottle, the bottle must be fixed steady with the height kept constant from the surface of the HPGe detecting device. In the past, there was not a correction container for sealing the space existing on the surface of the lower portion of a Marinelli beaker where the detecting device is contacted or another particular device or instrument capable of fixing on the correction container by changing a small measuring bottle.